An endoscope is connected optically removably to a TV camera through an adapter. A plurality of fixing pins is arranged on both sides of an insertion axis of an insertion part of the endoscope. A fixing unit to fix the endoscope removably is provided at the front end of an arm unit of an endoscope holder which supports the endoscope movably. The fixing unit has a claw and a movable claw, and grips the fixing pins of the endoscope releasably between the claw and the movable claw.